That'll do, pig... That'll do.
20-something litre box, simplicity, stuff it a bit with an old pillow, all good😀
SWEEET! - I have been approved as a used who can post in real time. Thanks moderators🙂
That's a surprisingly nice little change in the graphs, thankfully one which I can do down the road when I can get my hands on, and learn the basics of, a "800uF series (low loss)" capacitor. I've saved the image for future reference, thanks dude.
I'm not familiar with car audio so someone correct me if I'm wrong, but.....
Wouldn't a car door installation be considered closer to an infinite baffle and therefore any xo that is designed for that application fail to account for any baffle step loss? Using that same xo in a boxed speaker therefore would not result in a flat response but instead be sorely lacking in the bass department.
A separate baffle step compensation circuit may be necessary for what the OP is trying to do.
Not really sure if I'm right or wrong here? Can anybody else comment on this?
Wouldn't a car door installation be considered closer to an infinite baffle and therefore any xo that is designed for that application fail to account for any baffle step loss? Using that same xo in a boxed speaker therefore would not result in a flat response but instead be sorely lacking in the bass department.
A separate baffle step compensation circuit may be necessary for what the OP is trying to do.
Not really sure if I'm right or wrong here? Can anybody else comment on this?
There is a problem in using a car driver in a domestic environment: the crossover designed for a car assumes an infinite baffle, so no loss due to the baffle step effect. If you use such a driver with the car crossover on a "normal" enclosure, all the bass region will be low in SPL compared to the midrange and highs.
Ralf
Ralf
Yep, they'll be lacking in bass I'm sure... But first free simple project and all that - it doesn't matter much
Galu - many thanks for the link🙂
Galu - many thanks for the link🙂
Probably a better way of saying that is, the metric is so simple as to be useless, much like the single figure THD measurement.
dave
Floyd Toole, Sound reproduction Sound Reproduction
It is absoulutely full of useful stuff (but not without its blind spots). Probably the largest compendium of HiFi/acoustics related research published since Olsen.
Please do not buy from Amazon.
dave
I often see horizontal shelf braces in a box, they are not the most effective.(ref Tappan)
A brace should divide the panel such that the subpanels produced have a larger aspect ratio (and the 2 not the same) than the panel being braced.
dave
Aperiodic is a bit of a “squishy” term that can also be called a leaky sealed box, or a vented box with highly resistive vents.
Very useful when trying to tame a woofer with (not too much) high a Qt and/or to reduce the impedance rise at resonance and to attempt to completely absorb the back wave.
There are a number of ways to approach it — there are still no solid modeling tools). For your application, the receipe is to start with as large a sealed box as you can live with, damp it heavility and then start drilling small holes on the back as far from the driver as you can get. These holes should be heavily damped (i use open cel foam for this, but compressed fiberglass insulation is often used in simpler aperiodic vents. Start with a few holes and keep adding until done GM’s click-test or measuring the impedance and watching the resonance peak shrink are sutable metrics.
dave
Underdamped alignment. This kind of alignment is often used to give the impression of bass. The LS3/5A is an example (but i don’t think the bump is as large).
I start with a sort of similar shape in the curve when useing my miniOnken alignemt and then knock the peak down with a highly resistive vent (ie add damping). Given that mine are vented, the actual roll-off is 2x as fast as the sealed alignment shown.
dave
Well, stick them up against a wall, in a corner or on shelves surrounded by books and you shouldn't notice as much.
Or you can add a simple 2 component baffle step compensation circuit before the woofer which should take care of the problem as well.
That is somewhat confusing.
An IB should have no baffle step loss (the baffle is infinite). A car, with its much smaller volume, has significantly different room gain character. A car will, in general, have gan such that a low Q sealed box will be flat all the way down, vented boxes will turn the car into a boom box (often seems louder outside the car down low than inside).
dave
Thanx for the link, i don’t think i have seen that before.
This is the crude way to do an aperiodic box (basically just elaborating on Ted Jordan’s seminal work for Goodmans). This technique was put to good use in the Dyna A25 which had too big a woofer stuffed into too small a box.
Cabn be best emulated with fiberglass insulation squished between 2 pieces of plastic gutter mesh.
dave
You can find many more posts on aperiodic boxes by looking around my posts (planet10) with the search term "Pearl PR1”. An example: Sealed Box volume, easy, right?? AC8
The PR1 is one of the most well researched & effective aperiodic boxes developed to date.
dace
The PR1 is one of the most well researched & effective aperiodic boxes developed to date.
dace
On Galu’s link.
Here one can see an illustration of the affect on the impedance:
This is mirrored by the real world impedance measure of one of our aperiodic midTLs:
dave
Here one can see an illustration of the affect on the impedance:
This is mirrored by the real world impedance measure of one of our aperiodic midTLs:
dave
@ jjams82
Like Dave, I'm a fan of aperiodic loading and have posted about it in this forum.
If your sealed box sounds a bit 'honky' or 'boxed in' (apologies for the non-technical terms Dave!) then come back. I can guide you in regard to the diameter and number of holes to drill in the back of your box which, when felted internally, will result in aperiodic loading with its less resonant and more open sound.
Please let us know how your project evolves. Though 'simple', it has generated interest and information for a wider audience. 😎
Like Dave, I'm a fan of aperiodic loading and have posted about it in this forum.
If your sealed box sounds a bit 'honky' or 'boxed in' (apologies for the non-technical terms Dave!) then come back. I can guide you in regard to the diameter and number of holes to drill in the back of your box which, when felted internally, will result in aperiodic loading with its less resonant and more open sound.
Please let us know how your project evolves. Though 'simple', it has generated interest and information for a wider audience. 😎